[oldmanjay]

If you're under the impression that military spending has no expectation of return at all you aren't looking at things realistically.

[hx87]

Military spending resembles insurance to some extent--sure, the returns are normally terrible, but unexpected events that the spending covers are even more terrible.

[aninhumer]

Don't forget all the events that don't happen because of your military spending. A country with a weak military could be an attractive target.